Prior-art systems for the dumping of material in strip mines consist of a combination of a dumping belt, a traveling tripper and a stacker on crawlers.
The system lies on the dumped material and is moved forwards on same. In this case, the stacker is always close to the slope edge. This is possible as long as the dumped material generates a stable slope. In the case of unstable material, the heavy stack on the slope edge is, in particular, at risk. For the most part, the stability is improved by means of a specific dumping at the bottom of the slope. However, this requires a stacker with a long stacker boom. Nevertheless, if the slope is not stable, then the material has to be drained before dumping, which has the drawback of causing a great expense.